During railroad track construction, as well as major renewal of an existing railroad track, the track structure must be installed such that subsequent temperature variations or other weather conditions will not cause the rails to come loose or otherwise become unsafe. As a consequence, it is often necessary to carry out an operation on the rails referred to as "destressing." The destressing operation includes releasing rail fasteners, holding the rails to cross ties at a specific section of track, and heating or pulling the rails. Destressing the rails creates a finished track condition that is more capable of withstanding extreme temperature variations without the risk of deformation due to expansion and contraction of the rails.
Performing a destressing operation subsequent to the laying of the rails typically requires several additional steps in the railroad track construction process, as well as, additional specialized machinery. For example, U.S. Pat. No.: 4,903,611, issued to Holley on Feb. 27, 1990; U.S. Pat. No. 5,146,677, issued to Holman et al. on Sep. 15, 1992; and U.S. Pat. No. 5,269,225, issued to Bosshart et al. on Dec. 14, 1993, each disclose various machines and methods for performing a secondary destressing operation during railroad track construction or renewal. More particularly, the Holley patent shows an anchor spreader apparatus and method for using it with tie gangs, the Holman patent discloses a rail anchor remover mounted on a crane, and the Bosshart patent shows an apparatus and method for applying rail clips and insulators.
None of the prior art devices or methods have been found to be completely satisfactory. In particular, there has long been a need for a railroad track construction machine that is capable of laying or renewing rail without the need for a secondary destressing operation.